5 October 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown sand dunes in Herschel Basin, a large impact crater in the Terra Cimmeria region of Mars. The dunes of Herschel have grooved surfaces, indicating that their sands are somewhat cemented. Wind has blasted and eroded the cemented sand to form the grooves. This image was acquired in August 2004 and is located near 15.6S, 228.4W. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.